1. Field of the Invention
The present invention relates to a laser scanning microscope which scans a light flux from a light source, irradiates a sample with it and detects a fluorescence or reflected light from the sample, semiconductor laser light source unit, scanning unit for a laser scanning microscope, and a method of connecting a semiconductor light source to a scanning microscope.
2. Description of the Background Art
In recent years, development of a semiconductor light source has advanced, and wavelength bands of infrared/near infrared to red and blue can be covered. Based on this, in an apparatus using a laser as a light source, an effective use of a semiconductor laser has been demanded in order to enable a wavelength selection and a reduction in size of a light source and the apparatus. For example, U.S. Pat. No. 6,154,282 discloses a fluorescence microscope which utilizes a semiconductor light source.
FIG. 4 is a view showing a structure of a laser microscope disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-231222. In FIG. 4, a gas laser is used as a light source having a high brightness and the directivity. In FIG. 4, reference character A denotes a microscope unit and B designates a scanning head (scanning optical system main body).
The microscope unit A comprises a light source 101, an illumination lens 102, a beam splitter 103, an object lens 104, a sample 105, a condenser 106, a light source 107, a receiving device 108, a first body tube lens 109, a second body tube lens 110, a monitoring light beam path having an eyepiece lens 111, and a beam splitter 112 for combining the scanning light beams, and the light beam path can be switched by a swiveling mirror 114.
Laser modules 131 and 132 include lasers and are connected to the scanning head B through a visible light beam fibers 141 and 142. Coupling of the visible light beam fibers 141 and 142 is carried out by moving type collimator lenses 160 and 160 and light beam direction conversion elements 171 and 172.
In the scanning head B, a partial transmitting mirror 118 narrows down the monitoring light beam in a direction of a line path filter 151 and a monitor diode 119 on a neutral filter 150. The scanning unit consists of a scanning object lens 152, a scanner 153, a main beam splitter 154, and a common image forming lens 155 for detection channels 261 to 264. A direction conversion prism 157 reflects the light beam from the sample 105 in a direction of a dichroic beam splitter 158. A plurality of sets of a pin hole 159, a radiation filter 130 and a receiving element (PMT) 133 are arranged at the rear of the dichroic beam splitter 158.
The semiconductor laser radiates its outgoing beam with a spread based on its structure. Usually, this spread has a radiation characteristic which differs depending on horizontal/vertical directions, and optically has an astigmatic difference which is an aberration component. Therefore, in the arrangement of such an optical system having a regular spherical lens structure as disclosed in U.S. Pat. No. 6,154,282, the light source and the lens system cannot be efficiently optically combined with each other.
In case of using a technique which shapes the beam by using a cylindrical lens or a prism and leads it into the apparatus, the loss of the beam or the remanence of the astigmatic difference actually cannot be avoided.
Furthermore, as shown in FIG. 4, since a combined optical system using a laser light source and a plurality of lasers requires a very large space, it is set as an external light source different from the scanning head (scanning optical system main body) because of the structure of the apparatus.